There is now a body of evidence that metalloproteases (MP) are important in the uncontrolled breakdown of connective tissue, including proteoglycan and collagen, leading to resorption of the extracellular matrix. This is a feature of many pathological conditions, such as rheumatoid and osteoarthritis, corneal, epidermal or gastric ulceration; tumor metastasis or invasion; periodontal disease and bone disease. Normally these catabolic enzymes are tightly regulated at the level of their synthesis as well as at their level of extracellular activity through the action of specific inhibitors, such as alpha-2-macroglobulins and TIMPs (tissue inhibitors of metalloprotease), which form inactive complexes with the MP's.
Osteo- and Rheumatoid Arthritis (OA and RA respectively) are destructive diseases of articular cartilage characterized by localized erosion of the cartilage surface. Findings have shown that articular cartilage from the femoral heads of patients with OA, for example, had a reduced incorporation of radiolabeled sulfate over controls, suggesting that there must be an enhanced rate of cartilage degradation in OA (Mankin et al. J. Bone Joint Surg. 1970, 52A, 424–434). There are four classes of protein degradative enzymes in mammalian cells: serine, cysteine, aspartic and metalloproteases. The available evidence supports that it is the metalloproteases that are responsible for the degradation of the extracellular matrix of articular cartilage in OA and RA. Increased activities of collagenases and stromelysin have been found in OA cartilage and the activity correlates with severity of the lesion (Mankin et al. Arthritis Rheum. 1978, 21, 761–766, Woessner et al. Arthritis Rheum. 1983, 26, 63–68 and Woessner et al. Arthritis Rheum. 1984, 27, 305–312).
Therefore, metalloproteases (MP) have been implicated as the key enzymes in the destruction of mammalian cartilage and bone. It can be expected that the pathogenesis of such diseases can be modified in a beneficial manner by the administration of MP inhibitors, and many compounds have been suggested for this purpose (see Wahl et al. Ann. Rep. Med. Chem. 1990, 25, 175–184, AP, San Diego).
Tumor necrosis factor-α (TNF-α) is a cell-associated cytokine that is processed from a 26 kd precursor form to a 17 kd active form. TNF-α has been shown to be a primary mediator in humans and in animals, of inflammation, fever, and acute phase responses, similar to those observed during acute infection and shock. Excess TNF-α has been shown to be lethal. There is now considerable evidence that blocking the effects of TNF-α with specific antibodies can be beneficial in a variety of circumstances including autoimmune diseases such as rheumatoid arthritis (Feldman et al. Lancet 1994, 344, 1105), non-insulin dependent diabetes melitus (Lohmander, L. S. et al. Arthritis Rheum. 1993, 36, 1214–22) and Crohn's disease (MacDonald et al. Clin. Exp. Immunol. 1990, 81, 301).
Compounds which inhibit the production of TNF-α are therefore of therapeutic importance for the treatment of inflammatory disorders. Recently, TNF-α converting enzyme (TACE), the enzyme responsible for TNF-α release from cells, were purified and sequenced (Black et al. Nature 1997, 385, 729; Moss et al. Nature 1997, 385, 733). This invention describes molecules that inhibit this enzyme and hence the secretion of active TNF-α from cells. These novel molecules provide a means of mechanism based therapeutic intervention for diseases including but not restricted to septic shock, haemodynamic shock, sepsis syndrome, post ischemic reperfusion injury, malaria, Crohn's disease, inflammatory bowel diseases, mycobacterial infection, meningitis, psoriasis, congestive heart failure, fibrotic diseases, cachexia, graft rejection, cancer, diseases involving angiogenesis, autoimmune diseases, skin inflammatory diseases, OA, RA, multiple sclerosis, radiation damage, hyperoxic alveolar injury, periodontal disease, HIV and non-insulin dependent diabetes melitus.
Since excessive TNF-α production has been noted in several disease conditions also characterized by MMP-mediated tissue degradation, compounds which inhibit both MMPs and TNF-α production may also have a particular advantage in diseases where both mechanisms are involved.
Prostaglandins (PG) play a major role in the inflammation process and the inhibition of PG production has been a common target of anti-inflammatory drug discovery. Many NSAIDS have been found to prevent the production of PG by inhibiting the enzyme cyclooxygenase (COX). Among the two isoforms of COXs, COX-1 is constitutively expressed. COX-2 is an inducible isozyme associated with inflammation. Selective COX-2 inhibitor was believed to maintain the efficacy of traditional NSAIDs, which inhibit both isozymes, and produce fewer and less drastic side effects. As a result, development of selective COX-2 inhibitors has attracted major interest in the pharmaceutical industry. Because of the significant roles of PGs and TNF-α in inflammation, combined use of COX-2 and TACE inhibitors may have superior efficacy to either therapy alone in some inflammatory diseases.
U.S. Pat. No. 4,769,461 depicts leukotriene inhibitors of the formula:
wherein X and Y can be carbon or nitrogen, Z can be a variety of linking groups, W can be CH(OH), and R2 can be H. MMP and/or TACE inhibition is not mentioned. Compounds specifically described in U.S. Pat. No. 4,769,461 are not considered to be part of the present invention.
WO01/36365 illustrates thyroid receptor antagonists of the formula:
wherein R1 can be optionally substituted aryl or heteroaryl; X can be O, S, or N; R3 and R4 are required substituents that do not include hydrogen; Y can be a hydroxy- or alkoxy-substituted carbon atom; and R5 can be hydroxamic acid. MMP and/or TACE inhibition is not mentioned. Compounds specifically described in WO01/36365 are not considered to be part of the present invention.
WO98/05635 describes MMP and TACE inhibitors that are hydroxamic and carboxylic acid derivatives of the formula:B—X—(CH2)n—CHR1—(CH2)m—C(O)Ywherein Y is OH, alkoxy, or NHOH; X can be O; B can be alkyl; n can be 0, m can be 1, and R1 can be optionally substituted aryl or heteroaryl. Compounds specifically described in WO98/05635 are not considered to be part of the present invention.
JP-10087567 relates to kinase inhibitors of the formula:
wherein X can be a carbocyclic or heterocyclic ring, A can be a bond or alkylene, Y can be substituted alkylene, Z can be imino, B can be absent, and R3 can be an acyl group. MMP and/or TACE inhibition is not mentioned. Compounds specifically described in JP-10087567 are not considered to be part of the present invention.
It is desirable to find new compounds with improved pharmacological characteristics compared with known MMP and/or TACE inhibitors. For example, it is preferred to find new compounds with improved MMP and/or TACE inhibitory activity and selectivity for an MMP and/or TACE versus other metalloproteases (e.g., specificity for one MMP versus another). It is also desirable and preferable to find compounds with advantageous and improved characteristics in one or more of the following categories, but are not limited to: (a) pharmaceutical properties; (b) dosage requirements; (c) factors which decrease blood concentration peak-to-trough characteristics; (d) factors that increase the concentration of active drug at the receptor; (e) factors that decrease the liability for clinical drug-drug interactions; (f) factors that decrease the potential for adverse side-effects; and, (g) factors that improve manufacturing costs or feasibility.
The compounds of the present invention act as inhibitors of MPs, in particular TACE and/or MMPs, or a combination thereof. These novel molecules are provided as anti-inflammatory compounds and cartilage protecting therapeutics. The inhibition of TACE, and other metalloproteases by molecules of the present invention indicates they are anti-inflammatory and should prevent the degradation of cartilage by these enzymes, thereby alleviating the pathological conditions of OA and RA.